Bandwidth part adaptation in downlink communications

ABSTRACT

The present disclosure relates to a mobile terminal, a base station, an operating method for a mobile terminal and an operating method for a base station. The mobile terminal is for communicating in a mobile communication system with a base station using at least one of a first bandwidth part, BP1, and a second bandwidth part, BP2. Both, the first and second bandwidth part BP1 and BP2 are within a system bandwidth, wherein the first bandwidth part, BP1, is smaller than the second bandwidth part, BP2. The mobile terminal comprises a transceiver which, in operation, receives a configuration of a discontinuous reception, DRX, cycle. Further, the mobile terminal comprises a processor which, in operation, configures, upon reception of the configuration of the DRX cycle, the a downlink communication during at least one of the communication periods within the DRX cycle to use a specific one of at least the first bandwidth part, BP1, and the second bandwidth part, BP2.

BACKGROUND Technical Field

The present disclosure relates to the adaptation of bandwidth parts in amobile communication system to be utilized in combination withdiscontinuous reception for downlink communications between a mobileterminal and a base station.

Description of the Related Art

Currently, the 3^(rd) Generation Partnership Project (3GPP) focuses onthe next release (Release 15) of technical specifications for the nextgeneration cellular technology, which is also called fifth generation(5G).

At the 3GPP Technical Specification Group (TSG) Radio Access network(RAN) meeting #71 (Gothenburg, March 2016), the first 5G study item,“Study on New Radio Access Technology” involving RAN1, RAN2, RAN3 andRAN4 was approved and is expected to become the Release 15 work item(WI) which will defines the first 5G standard.

One objective of 5G new radio (NR) is to provide a single technicalframework addressing all usage scenarios, requirements and deploymentscenarios defined in 3GPP TSG RAN TR 38.913 v14.1.0, “Study on Scenariosand Requirements for Next Generation Access Technologies”, December 2016(available at www.3gpp.org and incorporated herein in its entirety byreference), at least including enhanced mobile broadband (eMBB),ultra-reliable low-latency communications (URLLC), massive machine typecommunication (mMTC).

For example, eMBB deployment scenarios may include indoor hotspot, denseurban, rural, urban macro and high speed; URLLC deployment scenarios mayinclude industrial control systems, mobile health care (remotemonitoring, diagnosis and treatment), real time control of vehicles,wide area monitoring and control systems for smart grids; mMTC mayinclude the scenarios with large number of devices with non-timecritical data transfers such as smart wearables and sensor networks.

Another objective is the forward compatibility, anticipating future usecases/deployment scenarios. The backward compatibility to Long TermEvolution (LTE) is not required, which facilitates a completely newsystem design and/or the introduction of novel features.

As summarized in one of the technical reports for the NR study item(3GPP TSG TR 38.801 v2.0.0, “Study on New Radio Access Technology; RadioAccess Architecture and Interfaces”, March 2017), the fundamentalphysical layer signal waveform will be based on Orthogonal FrequencyDivision Multiplexing (OFDM). For both downlink and uplink, OFDM withcyclic prefix (CP-OFDM) based waveform is supported. Discrete FourierTransformation (DFT) spread OFDM (DFT-S-OFDM) based waveform is alsosupported, complementary to CP-OFDM waveform at least for eMBB uplinkfor up to 40 GHz.

One of the design targets in NR is to utilize the fundamental physicallayer signal waveform in communications while reducing the overall powerconsumption. For this purpose it was agreed in the 3GPP RAN2 NR AdHoc #2meeting in Qingdao, China on 27-29 Jun. 2017 to apply mechanisms similarto discontinuous reception (DRX) in LTE in the downlink as a baselinedesign.

The term “downlink” refers to communication from a higher node to alower node (e.g., from a base station to a relay node or to a UE, from arelay node to a UE, or the like). The term “uplink” refers tocommunication from a lower node to the higher node (e.g., from a UE to arelay node or to a base station, from a relay node to a base station, orthe like). The term “sidelink” refers to communication between nodes atthe same level (e.g., between two UEs, or between two relay nodes, orbetween two base stations).

BRIEF SUMMARY

One non-limiting and exemplary embodiment facilitates adaptation ofbandwidth parts in a mobile communication system to be utilized incombination with discontinuous reception for downlink communicationsbetween a mobile terminal and a base station.

In one general aspect, the techniques disclosed here feature, a mobileterminal for communicating in a mobile communication system with a basestation using at least one of a first bandwidth part, BP1, and a secondbandwidth part, BP2. Both, the first and second bandwidth part BP1 andBP2 are within a system bandwidth, wherein the first bandwidth part,BP1, is smaller than the second bandwidth part, BP2. The mobile terminalcomprises a transceiver which, in operation, receives a configuration ofa discontinuous reception, DRX, cycle. Further, the mobile terminalcomprises a processor which, in operation, configures, upon reception ofthe configuration of the DRX cycle, the a downlink communication duringat least one of the communication periods within the DRX cycle to use aspecific one of at least the first bandwidth part, BP1, and the secondbandwidth part, BP2.

In another general aspect, the techniques disclosed here feature a basestation for communicating in a mobile communication system with a mobileterminal, using at least one of a first bandwidth part, BP1, and asecond bandwidth part, BP2. Both, the first and second bandwidth partBP1 and BP2 are within a system bandwidth, wherein the first bandwidthpart, BP1, is smaller than the second bandwidth part, BP2. The basestation comprises a transceiver which, in operation, transmits aconfiguration of a discontinuous reception, DRX, cycle. Further, thebase station comprises a processor which, in operation, configures, upontransmission of the configuration of the DRX cycle, a downlinkcommunication during at least one of the communication periods withinthe DRX cycle to use a specific one of at least the first bandwidthpart, BP1, and the second bandwidth part, BP2.

In a further general aspect, the techniques disclosed here feature anoperating method to be performed by a mobile terminal using at least oneof a first bandwidth part, BP1, and a second bandwidth part, BP2, withina system bandwidth, the first bandwidth part, BP1, being smaller thanthe second bandwidth part, BP2. The operating method comprises the stepsof receiving a configuration of a discontinuous reception, DRX, cycle;and configuring, upon reception of the configuration of the DRX cycle, adownlink communication during at least one of the communication periodswithin the DRX cycle to use a specific one of at least the firstbandwidth part BP1 and the second bandwidth part BP2.

In yet another general aspect, the techniques disclosed here feature anoperating method to be performed by a base station using at least one ofa first bandwidth part, BP1, and a second bandwidth part, BP2, within asystem bandwidth, the first bandwidth part, BP1, being smaller than thesecond bandwidth part, BP2. The operating method comprises the steps oftransmitting a configuration of a discontinuous reception, DRX, cycle;and configuring, upon transmission of the configuration of the DRXcycle, a downlink communication during at least one of the communicationperiods within the DRX cycle to use a specific one of at least the firstbandwidth part BP1, and the second bandwidth part BP2.

It should be noted that general or specific embodiments may beimplemented as a system, a method, an integrated circuit, a computerprogram, a storage medium, or any selective combination thereof.

Additional benefits and advantages of the disclosed embodiments will beapparent from the specification and Figures. The benefits and/oradvantages may be individually obtained by the various embodiments andfeatures of the specification and drawings, which need not all beprovided in order to obtain one or more of such benefits and/oradvantages.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIGS. 1 a-1 d are schematic drawings illustrating exemplarycommunications employing a discontinuous reception mechanism in NR;

FIG. 2 is a block diagram showing the structure of a mobile terminal anda base station;

FIGS. 3 a-3 d are schematic drawings illustrating one scheme ofbandwidth part adaptations in combination with the discontinuousreception mechanism in NR; and

FIGS. 4 a-4 d are schematic drawings illustrating another scheme ofbandwidth part adaptations in combination with discontinuous receptionmechanism in NR.

DETAILED DESCRIPTION

As identified in TR 38.913, the various use cases/deployment scenariosfor NR have diverse requirements in terms of data rates, latency, andcoverage. With these requirements in mind NR should aim for even furtherreduced power consumption, as compared with LTE.

In 3GPP RAN1 #86bis, it was agreed to employ a concept of bandwidthadaptation for downlink communications. This concept of bandwidthadaptation envisions the allocation of narrow bandwidth part within thesystem bandwidth. This bandwidth part shall facilitate the monitoring ofdownlink control information at reduced power consumption.

Particularly, it was agreed, at least for single carrier operation, thatNR should allow a UE to operate in a way where it receives at leastdownlink control information in a first RF bandwidth and where the UE isnot expected to receive in a second RF bandwidth that is larger than thefirst RF bandwidth within less than X μs (the value of X did remain forfurther study, FFS).

Aside of this general agreement, it remained for further study whetherthe first RF bandwidth is within the second RF bandwidth, whether thefirst RF bandwidth is at the center of the second RF bandwidth; and whatthe maximum ratio of the first RF bandwidth over the second RF bandwidthcan be. The detailed mechanism also remained for further study, as wellas how RF bandwidth adaptation works for radio resource management (RRM)measurements.

In 3GPP RAN1 #88bis, it was further agreed that, for single-carrieroperation, the UE is not required to receive any DL signals outside afrequency range A which is configured to the UE. The interruption timeneeded for frequency range change from frequency range A to a frequencyrange B needs to be defined (TBD). Additionally, the frequency ranges A& B may be different in BW and center frequency in a single carrieroperation.

In addition to the agreements, working assumptions were made: One ormultiple bandwidth part configurations for each component carrier can besemi-statically signaled to a UE. A bandwidth part consists of a groupof contiguous physical resource blocks (PRBs). Reserved resources can beconfigured within the bandwidth part. The bandwidth of a bandwidth partequals to or is smaller than the maximal bandwidth capability supportedby a UE. The bandwidth of a bandwidth part is at least as large as thesynchronization signal (SS) block bandwidth. The bandwidth part may ormay not contain the SS block.

Further working assumptions relate to the configuration of a bandwidthpart, which may include the following properties: Numerology, Frequencylocation (e.g., center frequency), and Bandwidth (e.g., number of PRBs).Note that the above working assumptions are for the RRC connected modeof an UE. It remained for further study (FFS) how to indicate to the UEwhich bandwidth part configuration (if multiple) should be assumed forresource allocation at a given time. Also the neighbor cell radioresource management (RRM) measurements remained for further study.

Subsequently, in 3GPP RAN1 #89, the above working assumptions wereconfirmed as agreement.

In this respect, it may be concluded that the bandwidth part (BP)adaptation for power saving relies on a following configuration: atleast two downlink BPs are semi-statically configured for a given UE,one is narrowband, and the other is wideband. Narrowband BP can beactivated for the UE if traffic is low. As a result, reception over anarrower bandwidth can provide power saving gain for the UE. A widebandBP can be activated for the UE if the traffic is high, in order to boostthe data rate.

Separate therefrom, in 3GPP RAN2 it was agreed to implement mechanismssimilar to the discontinuous reception (DRX) framework of LTE in thedownlink of NR. In the following, a brief introduction of a potentialimplementation to a DRX framework for NR will be given with respect todifferent examples of downlink communications.

Different examples of downlink communications are depicted in FIGS. 1a-1 d utilizing the DRX framework in NR. Particularly, all the FIGS. 1a-1 d show a downlink communication in NR between a base station (alsoreferred to as gNodeB or gNB) and a mobile terminal (also referred to asUE). So despite the necessity to also perform uplink communicationbetween the mobile terminal and the base station, this has been omittedin the figures and description for conciseness reasons only.

In general, the discontinuous reception framework is introduced toalleviate the necessity for the UE to continuously monitor the downlinkchannels. A DRX cycle consists of an “ON duration” during which the UEshould monitor the physical downlink control channel and a “DRX period”during which the UE can skip reception of downlink channels for batterysaving purposes.

The parameterization of the DRX cycle involves a trade-off betweenbattery saving and latency. On the one hand, a long DRX period isbeneficial for lengthening the UE's battery life. For example, in caseof short bursts of traffic demands, it is usually a waste of resourcesfor the UE to continuously monitor downlink channels while there is notraffic to meet the supply. On the other hand, a short DRX period isbetter for faster response when data transfers resumed.

The use of a DRX cycle is controlled by the gNodeB. For example, a UEmay be configured with a long DRX cycle and a short DRX cycle and thetransition between the two DRX cycles may be either controlled by atimer or by explicit commands from the gNodeB. The gNodeB may configurethe UE to transition to continuous reception, thereby setting the “ONduration” to the maximum and “DRX period” to zero.

The configuration of a DRX cycle involves at least three timers, namelythe “on duration” timer, the “inactivity” timer and the “retransmission”timer. With these three timers, in the DRX cycle the individualmonitoring durations for the UE are specified, namely the transmissionperiod for the gNodeB to transmit data and/or control signals to the UE,the inactive period which is trailing a transmission to the UE, andretransmission period(s) which would enable retransmissions in case ofcommunication failures.

Thus, the at least three timers determine for a DRX cycle the time whenthe UE has to monitor the downlink from the gNodeB, while for theremaining time it can assume a power saving state. At the end of a DRXcycle, the gNodeB controls the UE to repeat the DRX cycle or it controlsthe UE to transits to a different long/short DRX cycle, or even tocontinuous reception. The control is facilitated by a timer or byexplicit commands as discussed before.

Referring now to FIGS. 1 a-1 d in more detail:

Each of the Figures shows two DRX cycles #N and #N+1, both with a totalof 20 consecutive slots that may also be referred to as schedulingintervals. For example, the slots of both the DRX cycles #N and #N+1 maybe referred to with an individual numbers, such that the first slot of aDRX cycle is slot #0 and the last slot of the DRX cycle is slot #19.However, the slots can also be referred to with continuously increasingnumbers.

Additionally, it must be clarified that even though the followingdescription assumes that the scheduling interval for a downlink datatransmission is one slot, this shall not be construed as limiting thepresent disclosure. Rather, it may also be understood that onescheduling interval corresponds to one transmission time interval (TTI)in MAC layer which is defined using number of symbols. Taking intoconsideration the diverse requirements of different services in NR interms of data rates, latency and coverage, different TTIs areenvisioned. Different TTI durations therefore have different numbers ofsymbols, e.g., corresponding to a mini-slot, one slot, or multiple slotsin one transmission direction.

In FIG. 1 a , an example of two consecutive DRX cycles #N and #N+1 isshown with no downlink data transmissions from the gNodeB to the UE.Irrespective thereof, for both DRX cycles the UE is configured with a“ON duration” timer with a timer value of 2 slots. Thus, the UE wakes upduring time slots #0 and #1 of both DRX cycles #N and #N+1 to monitorthe physical downlink control channel for potential downlink assignment.

Assuming a similar operation of NR compared to LTE, the UE monitors (atleast) as long as the “ON duration” timer is running the physicaldownlink control channel (PDCCH) for scheduling assignments (downlinkresource allocations), namely for downlink control information (DCI)messages with a resource block (RB) assignment and a new data indicator(NDI) where the CRC is scrambled with the UE identity (i.e., a radionetwork temporary identifier (RNTI) of the UE, particularly the cellradio network temporary identifier (C-RNTI) of the UE). Thereby, the UEcan identify whether a downlink control information (DCI) message is forthe UE or not.

Having monitored the physical downlink control channel and havingdetected no downlink assignments for the UE, it goes in slot #2 back tosleep and continues to sleep for the remaining part of the DRX cycle #N.In other words, the UE is in a DRX period from slot #2 to slot #19 ofDRX cycle #N. Thereby, the power consumption for the downlinkcommunication can be reduced in the UE during DRX cycle #N. The samebehavior of the UE repeats for DRX cycle #N+1

It shall be pointed out that for this example that the “inactive”duration and the “retransmission” duration are not set off due to theabsence of any downlink assignments and downlink transmissions. Sincethere is no detected downlink assignment and there is no receiveddownlink transmission, the UE would not set off or reset the INACTIVEtimer. Additionally, in the absence of any downlink data transmissions,there could not be any communication failures that would require settingoff or starting the RETRANSMISSION timer.

In FIG. 1 b , an example of two consecutive DRX cycles #N and #N+1 isshown with downlink data transmissions from the gNodeB to the UE in DRXcycle #N and with no downlink data transmissions in DRX cycle #N+1.Irrespective thereof, for both DRX cycles the UE is configured with an“ON duration” timer with the value of 2. Thus, the UE wakes up (atleast) during time slots #0 and #1 of both DRX cycles #N and N+1 tomonitor the physical downlink control channel for potential downlinkassignments.

Due to the “ON duration” timer, the UE wakes up in slot #0 and monitorsthe physical downlink control channel. In this slot #0 the UE does notdetect a downlink assignment for the UE, which however changes for slots#1-#3.

Having detected, in slot #1, a scheduling assignment in the physicaldownlink control channel (e.g., downlink control information (DCI)message which includes a RB assignment for an initial transmission) forthe UE, it refers to the resource block(s) (RBs) indicated by thescheduling assignment in the physical downlink shared channel (PDSCH)and refers to the downlink data transmission in the indicated resourceblock(s). Thereby, in this slot #1, the UE receives the scheduleddownlink data transmission. Having received a downlink datatransmission, the UE resets the INACTIVE timer.

Similarly, in slots #2 and #3, the UE detects a downlink assignment inthe physical downlink control channel which schedules a downlink datatransmission in the same slots #2 and #3, respectively. Thus, also inslots #2 and #3, the UE receives the scheduled downlink datatransmission, and the UE resets, in each of these slots #2 and #3 theINACTIVE timer. Accordingly, in slot #3, the INACTIVE timer is still atits reset value, i.e., at the value of 3 slots.

As can be inferred from this example, the short “ON duration” period of2 slots does not limit the downlink data transmission to these two slotsonly. Rather, having been scheduled with a data transmission during aslot within the “ON duration” period, the UE does reset the INACTIVEtimer. During this time INACTIVE period, the UE remains monitoring thephysical downlink control channel for further downlink assignments.

In this example, the TRANSMISSION duration extends from slot #0 to slot#3, hence encompasses the period where the “ON duration” timer isrunning but is not restricted in this respect. Rather, the TRANSMISSIONduration shall be understood, in the context of the present disclosure,as time period which includes contiguous downlink data transmissionswhich have started while the “ON duration” timer is running but are notlimited in this respect.

Despite monitoring in slot #4 the physical downlink control channel, theUE does not receive a scheduling assignment. Thus, this slot #4 isconsidered part of the INACTIVE duration. And the INACTIVE timer will bedecreased by the value of 1 slot. Since in this example, the INACTIVEtimer was reset to 3 slots (=initial value) before slot #4, the INACTIVEduration includes the slots #4-#6.

In slot #7 the INACTIVE timer has expired such that UE goes to sleep.Also in slot #8 the UE is sleeping and does not monitor the physicaldownlink control channel.

As shown for slots #9-#11, the UE needs to wake-up for potentialretransmissions during a RETRANSMISSION duration which is provided forshould one of the (initial) downlink data transmissions have failed. TheRETRANSMISSION duration is separately configured for each (initial)downlink data transmission, e.g., per hybrid Automatic Repeat Request(HARQ) process.

In this example, only a single RETRANSMISSION duration is shown, namelythe one for the (initial) transmission in slot #1. Thus, the shownRETRANSMISSION duration is aligned with the initial transmission in slot#1, e.g., starts at a predetermined offset, in this example 8 slots. Inother words, the RETRANSMISSION duration starts at slot #9 for theinitial downlink data transmission in slot #1 and continues as long asthe RETRANSMISSION timer is running. It terminates earlier if the UE hasreceived the according downlink data retransmission.

Assuming a similar operation of NR compared to LTE, if the initialtransmission was not successfully decoded by the UE, the UE monitorsduring the RETRANSMISSION period the physical downlink control channel(PDCCH) for scheduling assignments, namely for downlink controlinformation (DCI) messages with a resource block (RB) assignment and nonew data indicator (NDI) but am indication of the corresponding HARQprocess, where again the CRC is scrambled with the UE identity (i.e., aradio network temporary identifier (RNTI) of the UE, particularly thecell radio network temporary identifier (C-RNTI) of the UE).

Having detected, as in slot #11, a scheduling assignment (e.g., adownlink control information (DCI) message which includes a RBassignment for the retransmission) for the UE, it refers to the resourceblock(s) (RBs) indicated by the scheduling assignment in the physicaldownlink shared channel (PDSCH) and receives the downlink dataretransmission in the indicated resource block(s) in slot #11. Notably,the downlink data retransmission does not set off any INACTIVE duration.

Since the downlink data retransmission has been received in slot #11,the UE goes in slot #12 back to sleep and continues to sleep for theremaining part of DRX cycle #N. In other words, the UE is in a DRXperiod from slot #12 to slot #19 of the DRX cycle #N. Same behavior ofthe UE going to sleep would have occurred in case the UE would not havenot received a downlink data retransmission, but instead theRETRANSMISSION timer has elapsed. Also hereby, the power consumption forthe downlink communication can be reduced in the UE during DRX cycle #N.

Regarding the behavior of the UE in DRX cycle #N+1 reference is onlymade to the description in FIG. 1 a for reasons of brevity.

In FIG. 1 c , an example of two consecutive DRX cycles #N and #N+1 isshown with downlink data transmissions from the gNodeB to the UE in DRXcycle #N and with no downlink data transmissions in DRX cycle #N+1. Theshown example of FIG. 1 c is very similar to the example in FIG. 1 b ,however, with the difference, that downlink data transmissions arereceived not only in slots #1-#3 but in slots #1-#6.

Due to these (extended) downlink data transmissions from the gNodeB tothe UE in DRX cycle #N, the INACTIVE duration after the (initial)downlink data transmissions overlaps with a RETRANSMISSION durationseparately configured for each (initial) downlink data transmission,e.g., per hybrid Automatic Repeat Request (HARD) process. In thisexample, only a single RETRANSMISSION duration is shown, namely the onefor the (initial) transmission in slot #1.

As will become apparent from the FIG. 1 c , the UEs operation during theRETRANSMISSION duration can coexist with over the behavior during theINACTIVE duration.

Again, due to the “ON duration” timer, the UE wakes up in slot #0 andmonitors the physical downlink control channel. In this slot #0 the UEdoes not detect a downlink assignment for the UE, which however changesfor slots #1-#6. In each of the slots #1-#6, the UE detects downlinkassignments in the physical downlink control channel which schedule adownlink data transmission in the same slots #1-#6, respectively.

Thus, in slots #1-#6, the UE receives the scheduled downlink datatransmission, and the UE resets, in each of these slots #1-#6 theINACTIVE timer. Accordingly, in slot #6, the INACTIVE timer is still atits reset value, i.e., at the value of 3 slots.

Despite monitoring in slot #7 the physical downlink control channel, theUE does not receive a scheduling assignment. Thus, this slot #7 isconsidered part of the INACTIVE duration. And the INACTIVE timer will bedecreased by the value of 1 slot. Since in this example, the INACTIVEtimer was reset to 3 slots (=initial value), the INACTIVE durationincludes the slots #7-#9.

As shown for slots #9-#11, the UE needs to wake-up for potentialretransmissions during a RETRANSMISSION duration which is provided forshould one of the (initial) downlink data transmissions have failed. TheRETRANSMISSION duration is separately configured for each (initial)downlink data transmission, e.g., per hybrid Automatic Repeat Request(HARM) process.

Again, in this example only a single RETRANSMISSION duration is shown,namely the one for the (initial) transmission in slot #1, and starts ata predetermined offset, corresponding to slot #9. From this slot onward,the RETRANSMISSION duration is shown for slots #9-#11.

Notably, in slot #9, the INACTIVE timer has not expired such that, forthis reason alone, the UE monitors the physical downlink controlchannel. However, since slots #9 also belongs to the RETRANSMISSIONperiod, the UE also monitors the physical downlink control channel forpotential downlink data retransmissions. These two behaviors of the UEdo not conflict but can be performed in coexistence.

In the example, in slot #11 the UE detects a scheduling assignment and,in the same slot #11 receives the corresponding downlink dataretransmission. Since the downlink data retransmission has been receivedin slot #11, the UE goes in slot #12 back to sleep and continues tosleep for the remaining part of DRX cycle #N. Also hereby, the powerconsumption for the downlink communication can be reduced in the UEduring DRX cycle #N.

Regarding the behavior of the UE in DRX cycle #N+1 reference is onlymade to the description in FIG. 1 a for reasons of brevity.

In FIG. 1 d , an example of two consecutive DRX cycles #N and #N+1 isshown with downlink data transmissions from the gNodeB to the UE in DRXcycle #N and with no downlink data transmissions in DRX cycle #N+1. Theshown example of FIG. 1 d is very similar to the examples in FIGS. 1 band 1 c , however, with the difference, that downlink data transmissionsare received in slots #1-#8.

Due to these (extended) downlink data transmissions from the gNodeB tothe UE in DRX cycle #N, the INACTIVE duration after the (initial)downlink data transmissions coincides with a RETRANSMISSION durationseparately configured for each (initial) downlink data transmission,e.g., per hybrid Automatic Repeat Request (HARD) process. In thisexample, only a single RETRANSMISSION duration is shown, namely the onefor the (initial) transmission in slot #1.

Referring now to FIG. 2 in more detail:

FIG. 2 illustrates a block diagram of a communication system including amobile terminal 210 and a base station 260 communication with each otherover a (wireless) physical channel 250. In the context of the presentdisclosure, however, reference will only be made to the downlinkcommunication between mobile terminal 210 and base station 260.

The mobile terminal 210 is for communicating in a mobile communicationsystem with a base station 260 using at least one of a first bandwidthpart, BP1, and a second bandwidth part, BP2. Both, the first and secondbandwidth part BP1 and BP2 are within a system bandwidth, wherein thefirst bandwidth part, BP1, is smaller than the second bandwidth part,BP2. The mobile terminal 210 comprises a transceiver 220 which, inoperation, receives a configuration of a discontinuous reception, DRX,cycle. Further, the mobile terminal 210 comprises a processor 230 which,in operation, configures, upon reception of the configuration of the DRXcycle, the a downlink communication during at least one of thecommunication periods within the DRX cycle to use a specific one of atleast the first bandwidth part, (BP1), and the second bandwidth part,BP2.

The base station 260 is for communicating in a mobile communicationsystem with a mobile terminal 210, using at least one of a firstbandwidth part, BP1, and a second bandwidth part, BP2. Both, the firstand second bandwidth part BP1 and BP2 are within a system bandwidth,wherein the first bandwidth part, BP1, is smaller than the secondbandwidth part, BP2. The base station 260 comprises a transceiver 270which, in operation, transmits a configuration of a discontinuousreception, DRX, cycle. Further, the base station 260 comprises aprocessor 280 which, in operation, configures, upon transmission of theconfiguration of the DRX cycle, a downlink communication during at leastone of the communication periods within the DRX cycle to use a specificone of at least the first bandwidth part, BP1, and the second bandwidthpart, BP2.

Also disclosed is a operating method to be performed by a mobileterminal using at least one of a first bandwidth part, BP1, and a secondbandwidth part, BP2, within a system bandwidth, the first bandwidthpart, BP1, being smaller than the second bandwidth part, BP2. Theoperating method comprises the steps of receiving a configuration of adiscontinuous reception, DRX, cycle; and configuring, upon reception ofthe configuration of the DRX cycle, a downlink communication during atleast one of the communication periods within the DRX cycle to use aspecific one of at least the first bandwidth part BP1 and the secondbandwidth part BP2.

Further disclosed is a operating method to be performed by a basestation using at least one of a first bandwidth part, BP1, and a secondbandwidth part, BP2, within a system bandwidth, the first bandwidthpart, BP1, being smaller than the second bandwidth part, BP2. Theoperating method comprises the steps of transmitting a configuration ofa discontinuous reception, DRX, cycle; and configuring, upontransmission of the configuration of the DRX cycle, a downlinkcommunication during at least one of the communication periods withinthe DRX cycle to use a specific one of at least the first bandwidth partBP1, and the second bandwidth part BP2.

In the following, the operation of a mobile terminal (also referred toas UE) and of a base station (also referred to as gNodeB or gNB)according to an exemplary embodiment is described with respect to FIGS.3 a-3 d and 4 a-4 d . In all the different examples, a downlinkcommunication between the gNodeB and the UE is to occur during at leastone of the communication periods specified in a discontinuous reception,DRX, cycle.

A DRX cycle includes different communication periods, for example theTRANSMISSION period, the INACTIVE period, and the RETRANSMISSION period.

During all these periods of the DRX cycle, the UE is required to atleast monitor the physical downlink control channel for potentialdownlink communication. At the same time, the DRX cycle also includesno-communication periods, which may also referred to as DRX period(s).During these no-communication periods the UE can skip reception ofdownlink channels for battery saving purposes.

Notably, not only the UE but also the gNodeB has to operate according toa same DRX cycle for successful downlink communications between the two.It would not be sufficient for (only) the UE to operate according to theDRX cycle. Then, the gNodeB would not know if a downlink communicationwas actually received by the UE. Thus, for successful downlinkcommunications both the UE and the gNodeB need to be configured with thesame DRX cycle. However, the gNodeB can be configured with multipledifferent DRX cycles, each corresponding to an individual UE.

As described before, in NR the concept of bandwidth part adaptation isintroduced, exemplarily, for downlink communication between the gNodeBand the UE. Due to the bandwidth part adaptation, it becomes possible tofurther alleviate the reception requirements for downlink communicationsbetween the gNodeB and the UE. Namely by assuming the usage of narrowbandwidth part UE can skip monitoring the system bandwidth outside ofthe adapted narrow bandwidth part. Thus, this concept can also beemployed for battery saving purposes.

Notably, also here not only the UE but also the gNodeB has to operateaccording to a same adapted bandwidth part for successful downlinkcommunications between the two. It would not be sufficient for (only)the UE to operate in an accordingly adapted bandwidth part. Then, thegNodeB would also not know if a downlink communication was actuallyreceived by the UE. Thus, for successful downlink communications, alsohere, the UE and the gNodeB need to have a common understanding with thesame adapted bandwidth part. Nevertheless, gNodeB can operate onmultiple bandwidth parts simultaneously, each for an individual UE.

In view of this understanding, the present disclosure combines bothmechanisms to attain a maximum amount of battery saving while at thesame time keeping the complexity of synchronizing both mechanisms at aminimum. It shall be emphasized that the combination of the twomechanisms reduces the reception requirements for the UE in time domainas well as frequency domain, thereby achieving a synergistic effectbetween the two.

The present disclosure does not stop at recognizing that both mechanismscan coexist in a mobile communication system. Rather, as part of thepresent disclosure it is recognized that there are specific combinationsof bandwidth part usages advantageously combine with the individualcommunication periods of a DRC cycle. In this respect, a semi-staticconfiguration of adapted bandwidth parts is suggested for at least oneof the communication periods in a DRX cycle.

In this respect, it is the underlying concept of the present disclosurethat the UE as well as the gNodeB already knows (e.g., by way ofsemi-static configuration) which specific one of two distinct bandwidthparts can be advantageously used during the at least one communicationperiod of the DRX cycle once the UE is configured by the gNodeB. Thisknowledge in the UE shall however, not prevent the gNodeB fromadditionally controlling the usage of bandwidth parts dynamically.Nevertheless, it is a prerequisite to the present disclosure that the UEand the gNodeB can use for downlink communication in a mobilecommunication system at least one first, narrow bandwidth part BP1 or asecond, wide bandwidth part BP2. On this basis, it can then be assumedthat the UE and the gNodeB refer to particular usage combinations in thefollowing table for the bandwidth part usage during the at least onecommunication period within a DRX cycle.

The bandwidth part usage combinations are summarized in the followingtable.

first second third fourth usage usage usage usage TRANSMISSION widenarrow narrow narrow duration of DRX bandwidth bandwidth bandwidthbandwidth cycle part BP2 part BP1 part BP1 part BP1 INACTIVE wide widenarrow narrow duration of DRX bandwidth bandwidth bandwidth bandwidthcycle part BP2 part BP2 part BP1 part BP1 RETRANSMISSION wide wide widenarrow duration of DRX bandwidth bandwidth bandwidth bandwidth cyclepart BP2 part BP2 part BP2 part BP1

Again it shall be emphasized that neither one of the above indicatedbandwidth part usage combinations restricts the downlink communicationto the respective one of the first or second bandwidth part for therespective one of the communication periods of the DRX cycle. Rather,the gNodeB may still, in addition, control the use of the bandwidthparts dynamically.

Referring to FIG. 3 a , an example of two consecutive DRX cycles #N and#N+1 with no downlink data transmissions from the gNodeB to the UE.Irrespective thereof, for both DRX cycles the UE is configured with a“ON duration” timer with a timer value of 2 slots. Thus, the UE wakes upduring time slots #0 and #1 of both DRX cycles #N and #N+1 to monitorthe physical downlink control channel for potential downlink assignment.

In this example, the UE and the gNodeB are configured according to thefourth bandwidth part usage combination (short: fourth usage). Thus, theUE monitors the physical downlink control channel in slots #0 and #1 ofboth DRX cycles #N and #N+1 using the first, narrow bandwidth part BP1.This fourth bandwidth part usage combination attains a maximum batterysaving effect for downlink communication between the gNodeB and the UE.

The fourth bandwidth part usage combination may be indicated by thegNodeB to the UE in advance, for example by way of a bandwidth usageindication, or may be indicated by the gNodeB to the UE at the same timeof configuring the DRX cycle. In both cases, the UE already knows, whenconfiguring the DRC cycle, which of the first or the second bandwidthparts it shall use during the individual communication periods of theDRX cycle.

In one exemplary implementation, the bandwidth usage indication may beincluded in a (dedicated) radio resource configuration, RRC, message. Inan alternative exemplary implementation, the bandwidth indication may beincluded in the RRC message configuring the DRX cycle. Furtheralternatives include a downlink control information, DCI, message or aMedium Access Control, MAC, Control Element.

The UE then monitors using the narrow bandwidth part, BP1, as specifiedfor the second usage, (at least) as long as the “ON duration” timer isrunning the physical downlink control channel (PDCCH) for schedulingassignments (downlink resource allocations), namely for downlink controlinformation (DCI) messages with a resource block (RB) assignment and anew data indicator (NDI) where the CRC is scrambled with the UE identity(i.e., a radio network temporary identifier (RNTI) of the UE,particularly the cell radio network temporary identifier (C-RNTI) of theUE). Thereby, the UE can identify whether a downlink control information(DCI) message is for the UE or not.

Having restricted the monitoring of the physical downlink controlchannel to the first, narrow bandwidth part, BP1, the UE benefits from areduced power consumption. At the same time the gNodeB has also to usefor downlink communications the same first, narrow bandwidth part, BP1.As already discussed with reference to FIG. 1 a , the UE goes in slot #2back to sleep and continues to sleep for the remaining part of the DRXcycle #N. The same behavior of the UE repeats for DRX cycle #N+1.

Referring to FIG. 3 b , an example of two consecutive DRX cycles #N and#N+1 is shown with downlink data transmissions from the gNodeB to the UEin DRX cycle #N and with no downlink data transmissions in DRX cycle#N+1.

In this example, the UE and the gNodeB are (again) configured accordingto the fourth bandwidth part usage combination (short: fourth usage).Thus, the UE monitors the physical downlink control channel in slots #0and #1 of both DRX cycles #N and #N+1 using the first, narrow bandwidthpart BP1. This fourth bandwidth part usage combination attains a maximumbattery savings effect for downlink communication between the gNodeB andthe UE.

Again, the fourth bandwidth part usage combination may be indicated bythe gNodeB to the UE in advance, for example by way of a bandwidth usageindication, or may be indicated by the gNodeB to the UE at the same timeof configuring the DRX cycle. In both cases, the UE already knows, whenconfiguring the DRC cycle, which of the first or the second bandwidthparts BP1 or BP2 it shall use during the individual communicationperiods of the DRX cycle.

Additionally, in this example, the UE is controlled by the gNodeB sothat it dynamically activates the second, wide bandwidth part fordownlink data transmissions from the gNodeB. When the UE detects ascheduling assignment for a downlink data transmission to itself, thenthe UE activates for the downlink data transmission in the indicated RBsthe second, wide bandwidth part, BP2. This second, wide bandwidth part,BP2 then remains activated for the remaining slots of the TRANSMISSIONduration.

Thus, with this dynamic activation the gNodeB utilizes for the (initial)downlink data transmissions the second, wide bandwidth part, BP2, to theUE, thereby maximizing throughput, whereas the UE can remain formonitoring purposes in the first, narrow bandwidth part, BP1, forbattery saving purposes. Hence, an advantageous combination of the twoconcepts is achieved.

It shall be emphasized, for this example, that the dynamic activation ofthe second, wide bandwidth part, BP2, and the deactivation of the first,narrow bandwidth part, BP1, does not require any separate signaling, forexample, included in the scheduling assignment received by the UE fromthe gNodeB. Rather, due to the fact that the UE activates the second,wide bandwidth part, BP2 in response to the detection of the (standard)scheduling assignment, it can use, without delay, the second, widebandwidth part, BP2, for the indicated downlink data transmission.

The dynamic activation of the second, wide bandwidth part BP2 isadvantageously limited to (remaining part of) the TRANSMISSION durationof only that DRX cycle. In a subsequent DRX cycle, the UE will startmonitoring the physical downlink control channel with the first, narrowbandwidth part BP1. Also, the dynamic activation of the second, widebandwidth part BP2 does not have any effect on the other communicationperiods of the same DRX cycle, namely the INACTIVE and theRETRANSMISSION duration.

Thus, with this dynamic activation, the throughput for downlinkcommunications between the gNodeB and the UE can be maximized, yet,retaining this effect for a short time frame only (i.e., thetransmission period), and, at the same time, avoiding any complexsignaling for the bandwidth part activation. In the remainder of the DRXcycle, a maximum battery savings effect due to the downlinkcommunication between the gNodeB and the UE being configured accordingto the fourth bandwidth part usage combination.

Referring to this example in more detail, due to the “ON duration”timer, the UE wakes up in slot #0 and monitors the physical downlinkcontrol channel. In this slot #0 the UE does not detect a downlinkassignment for the UE. Thus, for monitoring the physical downlinkcontrol channel in slot #0 the UE uses the first, narrow bandwidth part,BP1.

When detecting, in slot #1, a scheduling assignment in the physicaldownlink control channel (e.g., downlink control information (DCI)message which includes a RB assignment for an initial transmission) foritself, the UE also dynamically activates the second, wide bandwidthpart BP2.

The activation time for activating the second, wide bandwidth part BP2(and the deactivation of the first, narrow bandwidth part BP1) issufficient for the UE to refer to the resource block(s) (RBs) indicatedby the scheduling assignment in the physical downlink shared channel(PDSCH) and to receive the downlink data transmission in the indicatedresource block(s).

Thus, the UE receives, in this slot #1, the scheduled downlink datatransmission using the second, wide bandwidth part BP2. Having receiveda downlink data transmission, the UE proceed in slots #2 and #3 to alsoreceive downlink data transmissions using the second, wide bandwidthpart BP2. Thus, for the remainder of the TRANSMISSION duration, the UEremains in the second, wide bandwidth part BP2, thereby attainingmaximum throughput in the downlink communication of the DRX cycle #N.

Despite monitoring in slot #4 the physical downlink control channel, theUE does not receive a scheduling assignment. Thus, this slot #4 isconsidered part of the INACTIVE duration. Thus, for this slot #4 the UEactivates the first, narrow bandwidth part, BP1, (and deactivates thesecond, wide bandwidth part BP2), as specified by the fourth bandwidthpart usage combination. Thereby, the monitoring of the physical downlinkcontrol channel during the INACTIVE duration can be performed by the UEwith a maximum battery saving effect. The UE remains in the first,narrow bandwidth part, BP1, for the (entire) INACTIVE duration, namelynot only for slot #4 but also for slots #5 and #6. The motivation ofhaving such configuration is that it is most likely that UE entersINACTIVE time because the traffic burst is finished or close to the endwith only a few HARQ processes left. Due to low traffic demand inINACTIVE duration, UE can enjoy power saving by using narrow bandwidthpart, BP1, without sacrificing the possibility for gNodeB to communicatewith UE.

As shown for slots #9-#11, the UE needs to wake-up for potentialretransmissions during a RETRANSMISSION duration which is provided forshould one of the (initial) downlink data transmissions have failed. TheRETRANSMISSION duration is separately configured for each (initial)downlink data transmission, e.g., per hybrid Automatic Repeat Request(HARQ) process.

For the RETRANSMISSION duration, the UE again activates the first,narrow bandwidth part, BP1 (and deactivates the second, wide bandwidthpart BP2) as specified by the fourth bandwidth part usage combination.Thus also the monitoring and receiving of downlink data retransmissionsduring the RETRANSMISSION can be performed by the UE with a maximumbattery savings effect. As shown in FIG. 3 b , the RETRANSMISSIONduration occurs after the INACTIVE duration, meaning that the trafficburst is close to the end. Therefore, using narrow bandwidth part, BP1,would be sufficient for gNodeB to deliver the possible data.

In conclusion, the fourth bandwidth part usage combination attains amaximum battery saving effect for downlink communication between thegNodeB and the UE. Beneficially, in combination with the dynamicactivation during the TRANSMISSION duration, the throughput for at leastthe (initial) downlink data transmissions can also be improved in thesame DRX cycle. This advantageous combination does not even require anycomplex signaling, as discussed before.

With reference to FIGS. 3 c and 3 d further examples of two consecutiveDRX cycles #N and #N+1 are shown with downlink data transmissions fromthe gNodeB to the UE in DRX cycle #N and with no downlink datatransmissions in DRX cycle #N+1.

Also here, the UE and the gNodeB are configured according to the fourthbandwidth part usage combination (short: fourth usage), withadditionally, a dynamic activation of the second, wide bandwidth partBP2 for downlink data transmissions during the TRANSMISSION duration.Thus, this results in a similar usage of the first and second bandwidthparts BP1 and BP2 as compared with the downlink communication in FIG. 3b . Thus, a detailed description thereof is omitted herein for reasonsof brevity.

Yet, it shall be emphasized that irrespective of whether the individualcommunication periods of the DRX cycle are separate from each other intime (as in FIG. 3 b ), are overlapping each other in time (as in FIG. 3c ), or coincide with each other in time (as in FIG. 3 d ), thedefinition of the bandwidth part usage combinations always allows anunique identification of which specific one of the first or secondbandwidth parts BP1 and BP2 are to be activated, namely during theTRANSMISSION, INACTIVE and RETRANSMISSION duration of the DRX cycle.

Referring now to FIGS. 4 a-4 d , further examples of two consecutive DRXcycles #N and #N+1 are shown with the gNodeB communicating (or not) inthe downlink with the UE in the respective communication periods of theDRX cycle. In all these examples, the UE and the gNodeB are configuredaccording to the third bandwidth part usage combination (short: thirdusage), with additionally, a dynamic activation of the second, widebandwidth part BP2 for downlink data transmissions during theTRANSMISSION duration of the DRX cycle.

Thus, the UE activates the first, narrow bandwidth part, BP1, at thestart of the TRANSMISSION duration of the DRX cycles of all FIGS. 4 a-4d . Then, as shown in FIGS. 4 b-4 d , the detection of a schedulingassignment in the physical downlink control channel results in theactivation of the second, wide bandwidth part, BP2, and the usagethereof for downlink data transmissions. This second wide bandwidthpart, BP2 remains activated for the remainder of the TRANSMISSIONduration of the same DRX cycle.

After completion of the downlink data transmissions (also no furtherscheduling assignment are detected), the UE assumes the INACTIVEduration and, for this purpose, in slot #4 in FIG. 4 b , in slot #7 inFIG. 4 c , or in slot #9 in FIG. 4 d the first, narrow bandwidth part,BP1 is activated. This again complies with what is specified by thethird bandwidth part usage combination.

For the RETRANSMISSION period, starting at slot #9 in FIGS. 4 b-4 d ,the UE activates again the second, wide bandwidth part, BP2, formonitoring the physical downlink control channel and for potentiallyreceiving downlink data retransmissions over the physical downlinkshared channel. Due to the usage of the second, wide bandwidth part,BP2, a higher reliability for the downlink data retransmissions can beachieved, since the gNodeB has more freedom in the frequency domain toschedule the resources for retransmission which can bring lower coderate or/and better diversity Also with the usage of the second, widebandwidth part, BP2, the UE favorably uses also the same bandwidth partfor the downlink data retransmissions as for the (initial) downlink datatransmission. However, the power consumption could slightly increase,compared to the fourth usage as described before.

Different Dynamic Activation Mechanisms

In addition to the dynamic activation for downlink data transmissionsalready discussed above with reference to the figures, there aredifferent dynamic activation mechanisms that can be used to complementthe different semi-statically configured first to fourth bandwidth partusage combinations. All of the following mechanisms can be readilyapplied to downlink communication in the DRX cycles and result infurther advantages depending on the envisioned scenario.

In one mechanism, the UE dynamically activates the second, widebandwidth part, BP2, when it detects, during the RETRANSMISSIONduration, a scheduling assignment indicating a downlink dataretransmission for a corresponding (initial) transmission (e.g., via theHARQ information in the downlink control information, DCI, message).Then, the UE receives from the gNodeB the downlink data retransmissionusing the activated second, wide bandwidth part, BP2.

With this dynamic activation mechanism of the second, wide bandwidthpart, BP2, during the RETRANSMISSION duration, the gNodeB may be moreflexible in selecting resource block(s) to the scheduling assignment forthe downlink data retransmission. This flexibility may result in furtherimprovements to the reliability during the RETRANSMISSION duration,particularly if the gNodeB has to cope with higher number oftransmission failures.

It is immediately apparent that this dynamic activation of the second,wide bandwidth part BP2 during the RETRANSMISSION duration can becombined with the dynamic activation of the same second, wide bandwidthpart BP2 during the TRANSMISSION duration. Nevertheless, it must be keptin mind, that the every dynamic activation also consumes some battery,hence reduces the overall battery savings effect.

In another mechanism, the UE dynamically activates the same bandwidthpart (e.g., BP1 or BP2) to be used for the downlink data retransmissionsas in the (initial) downlink data transmission. This mechanism assumesthat an (initial) downlink data transmission between the gNodeB and theUE has failed during the TRANSMISSION duration, and that the UE detects,during the RETRANSMISSION duration, a scheduling assignment for theaccording retransmission. Then, in this mechanism, the UE activates thesame one of the bandwidth parts (BP1 or BP2) which was also used for the(initial) downlink data transmission.

Such a dynamic activation pattern may be advantageous if gNodeB wants toensure that it has the same bandwidth part at its disposal for the(initial) transmission as well as for the retransmission. If, one theone hand, the gNodeB does attribute a low priority to the (initial)transmissions to the UE, it may hereby also ensure that theretransmissions are also handled with a same low priority. If, on theother hand, the gNodeB does attribute a high priority to the (initial)transmission to the UE, then same holds true also for theretransmissions.

It is immediately apparent that the dynamic activation with the samebandwidth part for the retransmission as for the initial transmission,the gNodeB can enforce a same level of priority upon both transmissionseven when variably combining this mechanism with changing bandwidth partusage combinations. Also the same level of priority can be enforced ifthe dynamic activation of the second, wide bandwidth part, BP2, isfrequently changed.

In both dynamic mechanisms mentioned above, the DCI message carryingscheduling assignment itself can be used as the trigger for dynamicbandwidth part switching. Therefore, no additional bit field in DCI isneeded to explicitly indicate the bandwidth part switching.

In yet another mechanism, the gNodeB transmits to the UE in form of adownlink control information (DCI) message including an instruction toactivate a specific bandwidth part (BP1 or BP2) for the (entireduration) of a communication period of the DRX cycle. This may berealized by transmitting the DCI message in advance of the respectivecommunication period being one of the TRANSMISSION period, the INACTIVEperiod, and the RETRANSMISSION period.

In such case, a dedicated bit field in DCI to indicate the activatedbandwidth part is needed. The additional advantage of have the dedicatedbit field in DCI is to facilitate the bandwidth part indication ifmultiple wide and narrow bandwidth parts are configured for the UE. Insuch case, the activated one (either wide or narrow) can be indicatedby, e.g., bandwidth part index.

In response to the reception of the DCI message, the UE then configuresthe downlink communication with the gNodeB during the indicatedcommunication period of the DRX cycle to use the instructed bandwidthpart (BP1 or BP2).

Thereby the mechanism can even result in the dynamic activation of aninstructed bandwidth part (BP1 or BP2) for the entire duration of acommunication period of the DRX cycle. This is not possible with theother dynamic activation mechanisms which are all activating therespective bandwidth part only on demand, i.e., upon reception of ascheduling assignment. Thus, also this mechanism could complement thefirst to fourth bandwidth part usage combinations in an advantageousmanner, for example in case of instantaneous traffic demands.

Since different dynamic mechanisms imply different DCI structures, UEand gNodeB should have a common understanding of which one of the abovethree mechanisms is currently used. This common understanding can beestablished, e.g., by RRC signaling from gNodeB to UE.

Advantages of the Semi-Statically Configured First to Fourth Usage

The first to fourth bandwidth part usage combinations (short: first tofourth usages) have different advantages, and are intended for differentscenarios. Yet, they all have in common that either one of the first tofourth bandwidth part usage combinations specifies which of the first orsecond bandwidth part, BP1 or BP2, is to be used in all the differentcommunication periods during the DRX cycle. In other words, either oneof the first to fourth bandwidth usage combinations can be used for alldifferent communication timings of the DRX cycle.

The first to fourth bandwidth usage combinations can readily result in acommon understanding between the UE and the gNodeB which of the first orsecond bandwidth part, BP1 or BP2 is to be used during the entire DRXcycle. Thus, the first to fourth bandwidth usage combinations attain theadvantageous effect that the UE can receive downlink communicationsduring at least one, more particularly during all communication periodsof the DRX cycle to use a specific one of the first and second bandwidthparts BP1 or BP2.

For this purpose, the first to fourth bandwidth usage combination isindicated semi-statically from the gNodeB to the UE, for instance, in a(dedicated) radio resource configuration, RRC, message. In analternative exemplary implementation, the bandwidth indication may beincluded in the RRC message configuring the DRX cycle. Furtheralternatives include a downlink control information, DCI, message or aMedium Access Control, MAC, Control Element.

Alternatively, the first to fourth bandwidth usage combinations may alsobe specified in a suitable section in 3GPP technical standard of NR,such that the indication from the gNodeB to the UE only includes areference to the one of the first to fourth bandwidth usagecombinations. This could be achieved by, as few as two bits, providedthat both the gNodeB and the UE have a common understanding about whichof the first to fourth bandwidth usage combinations is to be used.Alternatively, the 3GPP technical standard specifications can specifythe relation between one of the four bandwidth usages with the UEcategory and/or service scenario. With such relationship, UEs belongingto one particular category and/or in a particular deployment scenariofollow one particular bandwidth usage combination. In such way, thesignaling overhead for configuration vanishes.

In a further alternative, the first to fourth bandwidth usagecombinations could be extended in that indication thereof requiresfurther information what the first, narrow bandwidth part, BP1, and whatthe second, wide bandwidth part, BP2, are. This is necessary,particularly, in a mobile communication system where multiple narrowbandwidth parts, and multiple wide bandwidth parts can are configuredover the system bandwidth.

In this case, the further information must complement the first tofourth bandwidth usage combinations such that it knows which of theconfigured different narrow and wide bandwidth parts to use as the firstand second bandwidth part BP1 and BP2 of the first to fourth bandwidthusage combinations. This further information can, for example, besignaled from the gNodeB to the UE in form of a downlink controlinformation (DCI) message.

Particularly, the signaling DCI message may include an index to selectthe first and/or second bandwidth part BP1, BP2 from among a pluralityof non-overlapping or overlapping narrow and wide bandwidth parts withinthe system bandwidth. Thus the semi-statically configured first tofourth bandwidth part usage combinations are also suitable for thisconfiguration of the mobile communication system.

Advantageously, the first bandwidth part usage combination (short: firstusage) always use wide bandwidth part, BP2, at the beginning of a DRXcycle. This facilitates the possible beam management procedure becausewide bandwidth part can be used for better beam measurement accuracy.The first bandwidth part usage also features no bandwidth part switchingover the whole communication period in a DRX cycle. This gives theadvantage of eliminating the bandwidth transition overhead. However,since no power saving gain by bandwidth part adaption is possible, thefirst bandwidth part usage can be used when traffic characteristics arecompleted known and the DRX cycle is configured accurately.

By contrast, for the second to four bandwidth part usage combinations,UE always activates narrow bandwidth part, BP1, when wakes up at eachDRX cycle. This can reduce the power consumption when UE wakes upunnecessarily. Therefore, the configuration of DRX cycle and OnDurationtimer can be more relaxed, compared to the first usage.

Advantageously, the second bandwidth part usage combination (short:second usage) only allows narrow to wide bandwidth part switching once ascheduling assignment is detected (e.g., by a dynamic mechanism) andthen maintains the wide bandwidth part for the rest of the DRX cycle.Since the wide bandwidth part can increase the peak data rate, such thatthe burst traffic can be served more quickly. This allows UE to get backto sleep earlier. Having a wide bandwidth part during the other timeperiods, such as INACTIVE time, can also provide more schedulingflexibility for the gNodeB. However, compared to the first usage, thissecond usage slightly increases the bandwidth part switching overhead.Nevertheless, it can beneficially be used, when traffic characteristicsare not completely, but largely known.

Advantageously, the third bandwidth part usage combination (short: thirdusage) prioritizes the retransmissions over or same as the (initial)transmissions, depending on which dynamic mechanism is used forbandwidth part activation once the scheduling assignment is detectedduring TRANSMISSION duration. Therefore, it provides reliableretransmission and makes efficient use of the bandwidth at high trafficloads.

Advantageously, the fourth bandwidth part usage combination (short:fourth usage) allows more bandwidth part switching to achieve betterpower saving, however, at the cost of an increased switching(transition) overhead. It can be beneficially applied when the trafficcharacteristics are unknown and hence DRX configuration cannot beconfigured matching the traffic burst. With the help of the fourthbandwidth part usage, the power saving gain can still be achieved.

The present disclosure can be realized by software, hardware, orsoftware in cooperation with hardware. Each functional block used in thedescription of each embodiment described above can be partly or entirelyrealized by an LSI such as an integrated circuit, and each processdescribed in the each embodiment may be controlled partly or entirely bythe same LSI or a combination of LSIs. The LSI may be individuallyformed as chips, or one chip may be formed so as to include a part orall of the functional blocks. The LSI may include a data input andoutput coupled thereto. The LSI here may be referred to as an IC, asystem LSI, a super LSI, or an ultra LSI depending on a difference inthe degree of integration. However, the technique of implementing anintegrated circuit is not limited to the LSI and may be realized byusing a dedicated circuit, a general-purpose processor, or aspecial-purpose processor. In addition, a FPGA (Field Programmable GateArray) that can be programmed after the manufacture of the LSI or areconfigurable processor in which the connections and the settings ofcircuit cells disposed inside the LSI can be reconfigured may be used.The present disclosure can be realized as digital processing or analogueprocessing. If future integrated circuit technology replaces LSIs as aresult of the advancement of semiconductor technology or otherderivative technology, the functional blocks could be integrated usingthe future integrated circuit technology. Biotechnology can also beapplied.

According to a first aspect, a mobile terminal is suggested forcommunicating in a mobile communication system with a base station usingat least one of a first bandwidth part and a second bandwidth partwithin a system bandwidth, the first bandwidth part being smaller thanthe second bandwidth part. The mobile terminal comprises a transceiverwhich, in operation, receives a configuration of a discontinuousreception, DRX, cycle; and a processor which, in operation, configures,upon reception of the configuration of the DRX cycle, a downlinkcommunication during at least one of the communication periods withinthe DRX cycle to use a specific one of at least the first bandwidthpart, and the second bandwidth part.

According to a second aspect, which can be combined with the firstaspect, the processor of the mobile terminal, in operation, configuresthe downlink communication according to a bandwidth usage indicationwhich indicates a usage of the specific one of at least the first andsecond bandwidth part during the at least one of the communicationperiod within the DRX cycle.

According to a third aspect, which can be combined with the secondaspect, the transceiver of the mobile terminal, in operation, receivesthe bandwidth usage indication via a radio resource configuration, RRC,message, a Downlink Control Information, DCI, message or a Medium AccessControl, MAC, Control Element.

According to a fourth aspect, which can be combined with the second orthird aspects, the transceiver of the mobile terminal, in operation,receives the bandwidth usage indication in a message also including theconfiguration of the DRX cycle.

According to a fifth aspect, which can be combined with the second tofourth aspect, the bandwidth usage indication indicates a usage of thespecific one of at least the first and second bandwidth part during atleast a TRANSMISSION duration, an INACTIVE duration, and anRETRANSMISSION duration within the DRX cycle and/or wherein thebandwidth usage indication indicates either a first usage including thesecond bandwidth part during the TRANSMISSION duration, the secondbandwidth part during the INACTIVE duration, and the second bandwidthpart during the RETRANSMISSION duration within the DRX cycle; or asecond usage including the first bandwidth part during the TRANSMISSIONduration, the second bandwidth part during the INACTIVE duration, andthe second bandwidth part during the RETRANSMISSION duration within theDRX cycle; or a third usage including the first bandwidth part duringthe TRANSMISSION duration, the first bandwidth part during the INACTIVEduration, and the second bandwidth part during the RETRANSMISSIONduration within the DRX cycle; or a forth usage including the firstbandwidth part during the TRANSMISSION duration, the first bandwidthpart during the INACTIVE duration, and the first bandwidth part duringthe RETRANSMISSION duration within the DRX cycle.

According to a sixth aspect, which can be combined with the first tofifth aspect, the processor of the mobile terminal, in operation,respectively configures the downlink communication during theTRANSMISSION duration or RETRANSMISSION duration to use the secondbandwidth part in case the transceiver receives a downlink schedulingassignment for a downlink transmission or re-transmission,

According to a seventh aspect, which can be combined with the first tosixth aspect, the processor of the mobile terminal, in operation,configures the communication during the RETRANSMISSION duration to usethe same of the first and second bandwidth part, as for the downlinkcommunication of the corresponding transmission during the TRANSMISSIONduration, in case the transceiver receives a downlink schedulingassignment for a downlink re-transmission.

According to a eighth aspect, which can be combined with the thirdaspect, the processor of the mobile terminal, in operation, configuresthe communication during the corresponding of the at least one of thecommunication periods within the DRX cycle to use instructed specificone of at least the first bandwidth part and the second bandwidth part,in case the transceiver receives a Downlink Control Information, DCI,message including an instruction to activate the specific one of atleast the first bandwidth part and the second bandwidth part during atleast one of the communication periods within the DRX cycle.

According to a ninth aspect, which can be combined with the first toeighth aspect, the transceiver of the mobile terminal, in operation,receives a configuration message, optionally a Downlink ControlInformation, DCI, message including: an index to select the first and/orsecond bandwidth part from among a plurality of non-overlapping oroverlapping narrow and wide bandwidth parts within the system bandwidth.

According to a tenth aspect, a base station is proposed forcommunicating in a mobile communication system with a mobile terminal,using at least one of a first bandwidth part, and a second bandwidthpart within a system bandwidth, the first bandwidth part being smallerthan the second bandwidth part. The base station comprises a transceiverwhich, in operation, transmits a configuration of a discontinuousreception, DRX, cycle; and a processor which, in operation, configures,upon transmission of the configuration of the DRX cycle, a downlinkcommunication during at least one of the communication periods withinthe DRX cycle to use a specific one of at least the first bandwidthpart, and the second bandwidth part.

According to an eleventh aspect, which can be combined with the tenthaspect, the processor of the base station, in operation, configures thedownlink communication according to a bandwidth usage indication whichindicates a usage of the specific one of at least the first and secondbandwidth part during the at least one of the communication periodwithin the DRX cycle.

According to a twelfth aspect, which can be combined with eleventhaspect, the transceiver of the base station, in operation, transmits thebandwidth usage indication via a radio resource configuration, RRC,message, a Downlink Control Information, DCI, message or a Medium AccessControl, MAC, Control Element.

According to a thirteenth aspect, which can be combined with eleventh ortwelfth aspect, the transceiver of the base station, in operation,transmits the bandwidth usage indication in a message also including theconfiguration of the DRX cycle.

According to a fourteenth aspect, which can be combined with theeleventh to thirteenth aspect, the bandwidth usage indication indicatesa usage of the specific one of at least the first and second bandwidthpart during at least a TRANSMISSION duration, an INACTIVE duration, andan RETRANSMISSION duration within the DRX cycle and/or wherein thebandwidth usage indication indicates either a first usage including thesecond bandwidth part during the TRANSMISSION duration, the secondbandwidth part during the INACTIVE duration, and the second bandwidthpart during the RETRANSMISSION duration within the DRX cycle; or asecond usage including the first bandwidth part during the TRANSMISSIONduration, the second bandwidth part during the INACTIVE duration, andthe second bandwidth part during the RETRANSMISSION duration within theDRX cycle; or a third usage including the first bandwidth part duringthe TRANSMISSION duration, the first bandwidth part during the INACTIVEduration, and the second bandwidth part during the RETRANSMISSIONduration within the DRX cycle; or a forth usage including the firstbandwidth part during the TRANSMISSION duration, the first bandwidthpart during the INACTIVE duration, and the first bandwidth part duringthe RETRANSMISSION duration within the DRX cycle.

According to a fifteenth aspect, which can be combined with the tenth tofourteenth aspect, the processor of the base station, in operation,respectively configures the downlink communication during theTRANSMISSION duration or RETRANSMISSION duration to use the secondbandwidth part, in case the transceiver transmits a downlink schedulingassignment for a downlink transmission or re-transmission.

According to a sixteenth aspect, which can be combined with the tenth tofifteenth aspect, the processor of the base station, in operation,configures the communication during the RETRANSMISSION duration to usethe same of the first and second bandwidth part, as for the downlinkcommunication of the corresponding transmission during the TRANSMISSIONduration, in case the transceiver transmits a downlink schedulingassignment for a downlink re-transmission.

According to a seventeenth aspect, which can be combined with the tenthto sixteenth aspect, the processor of the base station, in operation,configures the communication during the corresponding of the at leastone of the communication periods within the DRX cycle to use instructedspecific one of at least the first bandwidth part and the secondbandwidth part, in case the transceiver transmits a Downlink ControlInformation, DCI, message including an instruction to activate thespecific one of at least the first bandwidth part and the secondbandwidth part during at least one of the communication periods withinthe DRX cycle.

According to a eighteenth aspect, which can be combined with the tenthto seventeenth aspect, the transceiver of the base station, inoperation, transmits a configuration message, optionally a DownlinkControl Information, DCI, message including: an index to select thefirst and/or second bandwidth part from among a plurality ofnon-overlapping or overlapping narrow and wide bandwidth parts withinthe system bandwidth.

According to a nineteenth aspect, an operating method for a mobileterminal is suggested to communicate in a mobile communication systemwith a base station using at least one of a first bandwidth part, and asecond bandwidth part within a system bandwidth, the first bandwidthpart being smaller than the second bandwidth part. The method comprisesthe steps of receiving a configuration of a discontinuous reception,DRX, cycle; and configuring, upon reception of the configuration of theDRX cycle, a downlink communication during at least one of thecommunication periods within the DRX cycle to use a specific one of atleast the first bandwidth part and the second bandwidth part.

According to a twentieth aspect, an operating method for a base stationis suggested to communicate in a mobile communication system with amobile terminal, using at least one of a first bandwidth part, and asecond bandwidth part within a system bandwidth, the first bandwidthpart being smaller than the second bandwidth part. The method comprisesthe steps of transmitting a configuration of a discontinuous reception,DRX, cycle; and configuring, upon transmission of the configuration ofthe DRX cycle, a downlink communication during at least one of thecommunication periods within the DRX cycle to use a specific one of atleast the first bandwidth part, and the second bandwidth part.

The various embodiments described above can be combined to providefurther embodiments. All of the U.S. patents, U.S. patent applicationpublications, U.S. patent applications, foreign patents, foreign patentapplications and non-patent publications referred to in thisspecification and/or listed in the Application Data Sheet areincorporated herein by reference, in their entirety. Aspects of theembodiments can be modified, if necessary to employ concepts of thevarious patents, applications and publications to provide yet furtherembodiments.

These and other changes can be made to the embodiments in light of theabove-detailed description. In general, in the following claims, theterms used should not be construed to limit the claims to the specificembodiments disclosed in the specification and the claims, but should beconstrued to include all possible embodiments along with the full scopeof equivalents to which such claims are entitled. Accordingly, theclaims are not limited by the disclosure.

The invention claimed is:
 1. A communication apparatus for communicatingwith a base station comprising: a transceiver which, in operation,receives a first control information relating to a discontinuousreception (DRX) cycle; and circuitry which, in operation, configures fora downlink communication, upon reception of the first controlinformation, at least a first bandwidth part used for a first case or asecond bandwidth part used for a second case which is different from thefirst case, the second bandwidth part being different from the firstbandwidth part.
 2. The communication apparatus according to claim 1,wherein a specific one of at least the first bandwidth part or thesecond bandwidth part is indicated by a second control information via adownlink control information (DCI) at a same time of the reception ofthe first control information.
 3. The communication apparatus accordingto claim 1, wherein a specific one of at least the first bandwidth partor the second bandwidth part is indicated by a second controlinformation via a radio resource configuration (RRC) message, a downlinkcontrol information (DCI), or a medium access control (MAC) controlelement.
 4. The communication apparatus according to claim 2, whereinthe specific one of at least the first bandwidth part or the secondbandwidth part is used for a TRANSMISSION duration and a correspondingRETRANSMISSION duration of the downlink communication.
 5. Thecommunication apparatus according to claim 3, wherein the specific oneof at least the first bandwidth part or the second bandwidth part isused for a TRANSMISSION duration and a corresponding RETRANSMISSIONduration of the downlink communication.
 6. A base station forcommunicating with a communication apparatus comprising: a transceiverwhich, in operation, transmits a first control information relating to adiscontinuous reception (DRX) cycle; and circuitry which, in operation,configures for a downlink communication, upon transmission of the firstcontrol information, at least a first bandwidth part used for a firstcase and a second bandwidth part used for a second case which isdifferent from the first case, the second bandwidth part being differentfrom the first bandwidth part.
 7. The base station according to claim 6,wherein a specific one of at least the first bandwidth part or thesecond bandwidth part is indicated by a second control information via adownlink control information (DCI) at a same time of the transmission ofthe first control information.
 8. The base station according to claim 6,wherein a specific one of at least the first bandwidth part or thesecond bandwidth part is indicated by a second control information via aradio resource configuration (RRC) message, a downlink controlinformation (DCI), or a medium access control (MAC) control element. 9.The base station according to claim 7, wherein the specific one of atleast the first bandwidth part or the second bandwidth part is used fora TRANSMISSION duration and a corresponding RETRANSMISSION duration ofthe downlink communication.
 10. The base station according to claim 8,wherein the specific one of at least the first bandwidth part or thesecond bandwidth part is used for a TRANSMISSION duration and acorresponding RETRANSMISSION duration of the downlink communication. 11.A communication method performed by a communication apparatuscomprising: receiving a first control information relating to adiscontinuous reception (DRX) cycle; and configuring for a downlinkcommunication, upon reception of the first control information, at leasta first bandwidth part used for a first case and a second bandwidth partused for a second case which is different from the first case, thesecond bandwidth part being different from the first bandwidth part. 12.The communication method according to claim 11, wherein a specific oneof at least the first bandwidth part or the second bandwidth part isindicated by a second control information via a downlink controlinformation (DCI) at a same time of the reception of the first controlinformation.
 13. The communication method according to claim 11, whereina specific one of at least the first bandwidth part or the secondbandwidth part is indicated by a second control information via a radioresource configuration (RRC) message, a downlink control information(DCI), or a medium access control (MAC) control element.
 14. Thecommunication method according to claim 12, wherein the specific one ofat least the first bandwidth part or the second bandwidth part is usedfor a TRANSMISSION duration and a corresponding RETRANSMISSION durationof the downlink communication.
 15. The communication method according toclaim 13, wherein the specific one of at least the first bandwidth partor the second bandwidth part is used for a TRANSMISSION duration and acorresponding RETRANSMISSION duration of the downlink communication. 16.A communication method performed by a base station comprising:transmitting a first control information relating to a discontinuousreception (DRX) cycle; and configuring for a downlink communication,upon transmission of the first control information, at least a firstbandwidth part used for a first case and a second bandwidth part usedfor a second case which is different from the first case, the secondbandwidth part being different from the first bandwidth part.
 17. Thecommunication method according to claim 16, wherein a specific one of atleast the first bandwidth part or the second bandwidth part is indicatedby a second control information via a downlink control information (DCI)at a same time of the transmission of the first control information. 18.The communication method according to claim 16, wherein a specific oneof at least the first bandwidth part or the second bandwidth part isindicated by a second control information via a radio resourceconfiguration (RRC) message, a downlink control information (DCI), or amedium access control (MAC) control element.
 19. The communicationmethod according to claim 17, wherein the specific one of at least thefirst bandwidth part or the second bandwidth part is used for aTRANSMISSION duration and a corresponding RETRANSMISSION duration of thedownlink communication.
 20. The communication method according to claim18, wherein the specific one of at least the first bandwidth part or thesecond bandwidth part is used for a TRANSMISSION duration and acorresponding RETRANSMISSION duration of the downlink communication. 21.The communication apparatus according to claim 1, wherein each frequencyposition of the first bandwidth part and the second bandwidth part isindicated by a third control information.
 22. The communicationapparatus according to claim 2, wherein each frequency position of thefirst bandwidth part and the second bandwidth part is indicated by athird control information.
 23. The communication apparatus according toclaim 3, wherein each frequency position of the first bandwidth part andthe second bandwidth part is indicated by a third control information.24. The communication apparatus according to claim 4, wherein eachfrequency position of the first bandwidth part and the second bandwidthpart is indicated by a third control information.
 25. The base stationaccording to claim 6, wherein each frequency position of the firstbandwidth part and the second bandwidth part is indicated by a thirdcontrol information.
 26. The base station according to claim 7, whereineach frequency position of the first bandwidth part and the secondbandwidth part is indicated by a third control information.
 27. The basestation according to claim 8, wherein each frequency position of thefirst bandwidth part and the second bandwidth part is indicated by athird control information.
 28. The base station according to claim 9,wherein each frequency position of the first bandwidth part and thesecond bandwidth part is indicated by a third control information.